The subject invention is directed toward the art of rotary cutting tools and, more particularly, to that class of tools known as end milling cutters.
The invention is especially suited for incorporation in cutters formed from high speed tool steel and used for metal removal operations and will be described with reference thereto; however, as will become apparent, the invention is capable of broader application and could be incorporated in cutters formed of other materials and used for other types of cutting or material removal operations.
One of the primary goals in the design of milling cutters or end mills has been to produce a cutter capable of rapidly removing substantial quantities of material while leaving a comparatively smooth surface on the workpiece. In addition, it is, of course, desirable to have low power requirements for driving the tool and improved tool life.
To the above ends, the prior art has tried a variety of cutting edge configurations and designs. These designs have included "toothed" and intermittent edges and/or the incorporation of "chip-breaking" grooves in the faces of the cutting edges or the body of the cutter.
The most successful designs to date have involved the use of cutting edges having an undulating or sinusoidal configuration. Milling cutters of this general design are shown, for example, in U.S. Pat. Nos. 1,840,852 to Schotthoefer; 3,133,339 and 3,775,819 to Ribich; and 4,212,568 to Minicozzi. In these patents the cutting edges are given a sinusoidal configuration with the sine wave in each successive edge being slightly off-set from the preceding edge. By use of these edge configuration chip formation and chip removal is facilitated. In addition, when the entire sinusoidal edge lies at a uniform distance from the center axis of the cutter (i.e., there is no radial height difference along the cutting edge) a relatively smooth surface is produced on the workpiece.